Building Helical Antennas

We are using left hand winding on this antenna to match the first helical.

Super Glue. Pretty strong stuff.

Gloves are a good idea when working with Super Glue.

Wrapping is a pain. you need two people. vice grips are a recommended item for this.

Wrap tightly to keep on track. remember. there is no world Super Glue shortage.

We could have used a pie tin like the first antenna, but decided to use galvanized tin instead.

On this antenna we decided not to go through the endcap / copper tape nightmare and glued directly to the reflector. We have not tested this yet. hopefully it will work.

To adjust for not having a bolted down endcap, we decided to use a lot of caulk

Put the caulk in here.

Here is a shot of dan reminding us that caulk isn’t funny.

Pay attention on choosing the right PVC pipe.

The Hecker design relies on thin wall material such as under-sink drain pipe. High pressure pipe (thick wall) is a poor choice as the velocity factor of the dielectric has a significant impact on overall tuning.

Helixcalc and others assume open air or close to it. I placed a unit built with high pressure PVC and Hecker’s dimensions on a HP 8720D network analyzer only to find it was optimized for some freq considerably lower than 2425 MHz. See http://www.qsl.net/pa0hoo/helix_wifi/index_eng.htm